/*******************************************************************************
* SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU Lesser General Public License Version 2.1 or later (the
* "LGPL"), in which case the provisions of the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of the LGPL, and not to allow others to use your version of
* this file under the terms of the EPL, indicate your decision by deleting
* the provisions above and replace them with the notice and other provisions
* required by the LGPL. If you do not delete the provisions above, a recipient
* may use your version of this file under the terms of the EPL or the LGPL.
* 
* Based on the original MiniSat specification from:
* 
* An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the
* Sixth International Conference on Theory and Applications of Satisfiability
* Testing, LNCS 2919, pp 502-518, 2003.
*
* See www.minisat.se for the original solver in C++.
* 
*******************************************************************************/
package org.sat4j.minisat.constraints.cnf;

import org.sat4j.minisat.core.ILits;
import org.sat4j.specs.IVecInt;

public class DefaultWLClause extends WLClause {

    private boolean learnt;

    public DefaultWLClause(IVecInt ps, ILits voc) {
        super(ps, voc);
    }

    /**
     * 
     */
    private static final long serialVersionUID = 1L;

    /**
     * declares this clause as learnt
     * 
     */
    public void setLearnt() {
        learnt = true;
    }

    /*
     * (non-Javadoc)
     * 
     * @see org.sat4j.minisat.datatype.Constr#learnt()
     */
    public boolean learnt() {
        return learnt;
    }

    /**
     * Register this clause which means watching the necessary literals If the
     * clause is learnt, setLearnt() must be called before a call to register()
     * 
     * @see #setLearnt()
     */
    public void register() {
        assert lits.length > 1;
        if (learnt) {
            // prendre un deuxieme litt???ral ??? surveiller
            int maxi = 1;
            int maxlevel = voc.getLevel(lits[1]);
            for (int i = 2; i < lits.length; i++) {
                int level = voc.getLevel(lits[i]);
                if (level > maxlevel) {
                    maxi = i;
                    maxlevel = level;
                }
            }
            int l = lits[1];
            lits[1] = lits[maxi];
            lits[maxi] = l;
        }

        // ajoute la clause a la liste des clauses control???es.
        voc.watch(lits[0] ^ 1, this);
        voc.watch(lits[1] ^ 1, this);
    }

}
